update changes

app/views/projects/blob/viewers/_gitlab_ci_yml_loading.html.haml

-= icon('spinner spin fw')
+.spinner.spinner-md.fw
 Validating GitLab CI configuration…
 
 = link_to 'Learn more', help_page_path('ci/yaml/README')

app/views/projects/blob/viewers/_loading.html.haml

-.text-center.gl-mt-3.gl-mb-3
-  = icon('spinner spin 2x', 'aria-hidden' => 'true', 'aria-label' => 'Loading content…', class: 'qa-spinner')
+.text-center.prepend-top-default.append-bottom-default
+%gl-loading-icon{ "aria-hidden" => "true", "aria-label" => "Loading content…" }
+.qa-spinner
+

app/views/projects/blob/viewers/_loading_auxiliary.html.haml

-= icon('spinner spin fw')
+.spinner.spinner-md.fw
 Analyzing file…

app/views/projects/blob/viewers/_route_map_loading.html.haml

-= icon('spinner spin fw')
+.spinner.spinner-md.fw
 Validating Route Map…
 
 = link_to 'Learn more', help_page_path('ci/environments/index.md', anchor: 'going-from-source-files-to-public-pages')

app/views/projects/blob/viewers/_sketch.html.haml

 .file-content#js-sketch-viewer{ data: { endpoint: blob_raw_path } }
-  .js-loading-icon.text-center.gl-mt-3.gl-mb-3.js-loading-icon{ 'aria-label' => 'Loading Sketch preview' }
-    = icon('spinner spin 2x', 'aria-hidden' => 'true');
+  .js-loading-icon.text-center.prepend-top-default.append-bottom-default.js-loading-icon{ 'aria-label' => 'Loading Sketch preview' }
+   %gl-loading-icon{ "aria-hidden" => "true"}
+

app/views/projects/blob/viewers/_stl.html.haml

 .file-content.is-stl-loading
   .text-center#js-stl-viewer{ data: { endpoint: blob_raw_path } }
-    = icon('spinner spin 2x', class: 'gl-mt-3 gl-mb-3', 'aria-hidden' => 'true', 'aria-label' => 'Loading')
-  .text-center.gl-mt-3.gl-mb-3.stl-controls
+   %gl-loading-icon{ "aria-hidden" => "true", "aria-label" => "Loading" }
+   .prepend-top-default.append-bottom-default
+  .text-center.prepend-top-default.append-bottom-default.stl-controls
     .btn-group
       %button.btn.btn-default.btn-sm.js-material-changer{ data: { type: 'wireframe' } }
         Wireframe